Conditional checks on drill through report prompts

Cognos 7.4 MR2 and ReportNet 1.1 MR4
I have a drill through report that is working fine. The cube has several dimensions each with several levels. For example; Location, the user selects 'North America', then selects 'US', then 'Michigan' and then drills through to a report. The report then uses the filters Location1 ('North America'). Location2 ('US'), and Location3 ('Michigan') to select the data from the db. All of this work fine, but I could improve performance if I just passed Location3 in the query. Is there a way to check the parameters and only pass the lowest dimension sent from the cube? Thanks.